When a working machine such as a crawler crane is disassembled and stored, or disassembled and transported, a plurality of long attachments such as booms or struts are stacked in a vertical direction and secured so as not to collapse.
Examples of this type of technique include inventions disclosed in Patent Documents 1 and 2 listed below. In Patent Document 1, connecting tools called a fork end and an eye end are respectively secured to respective facing portions of a front mast and a rear mast to be stacked in a vertical direction, and these connecting tools are connected with each other by a pin. In Patent Document 2, lugs are respectively secured to respective facing portions of intermediate booms to be stacked in a vertical direction, and these lugs are connected with each other by a connecting pin.